Bag closure



1963 P. P. SPOLYSINO BAG CLOSURE 3 Sheets-Sheet 1 Original Filed Dec.23, 1964 Oct. 29, 1968 P. P. SPOLSINO 3,407,989

BAG CLOSURE Original Filed Dec. 23, 1964 I i 5 Sheets-Sheet 2.

1953 P. P. SPOLSINO BAG CLOSURE 5 Sheets-Sheet 5 Original Filed Dec. 23,1964 United States Patent ABSTRACT OF THE DISCLOSURE A double closure ofthermoplastic bags wherein a tape sleeve encircles the outer extremityof the bags gathered neck, the outer edge of the tape and the outer edgeof the thermoplastic bag being substantially flush and the outer edge ofthe bag that is substantially flush with the outer edge of the tapebeing fused.

This application is a division of my copending application Ser. No.420,720 filed Dec. 23, 1964, now Patent No. 3,323,272, which is acontinuation-in-part of my application Ser. No. 312,696, filed Sept. 30,1963, now US. Patent 3,187,481, which was in turn a continuationin-partof Ser. No. 163,168, filed Dec. 29, 1961, now US. Patent No. 3,111,794.

This invention relates to a sealed bag sealing. In one aspect theinvention relates to a method for sealing the gathered end of athermoplastic bag so as to obtain an air tight seal.

A common method of sealing the open end of thermoplastic bags requiresthat opposite sides of the open mouth be brought together and thatsufiicient heat be applied to the thermoplatsic material to fuse the twosides together. This necessarily results in a rather wide closureextending the width of the package which, while suitable for packagingsome products, is equally unsuitable for others. For example, whenpackaging whole poultry or primal meat cuts, it is preferred that thebag, including the sealed area, closely conform to the product.Conventional heat scaling, therefore, produces seals that lie somedistance from the end of the product and are relatively straight, loosefitting seals.

Another method of closing bags (and one that permits the sealed area tomore closely conform to the product) involves the application of adeformable metal band about the gathered end of the bag. The clip can beapplied to the gathered end of the bag in close proximity to the bz'ggedproduct. With the development of clip applying dr vices and suitableclips, it is now possible with this method to quickly obtain reliableseals. Several problems exist in connection wit-h clip sealing, the mostserious of which is the difficulty in obtaining an air tight closure.The gathered neck of the bag about which the clip is applied has amyriad of channels created by the folding of the bag through which aircan pass into the interior of the bag. To close off these channels, itis necessary to apply the clips tightly around the gathered neck of thebag. Because the bags of thermoplastic material are relatively fragile,the use of sufficient pressure to close the air passages is likely tocause the clip to tear into the bagdestroying the integrity of theclosure. The problem is even even more serious with large bags, sincecorresponding greater pressures must be applied to Seal the bag.

While it would theoretically be possible to heat fuse the gathered neckof a thermoplastic bag, this is not practical, since the fused materialmust be held under restraint or otherwise supported while the materialis cooling and solidifying. A not inconsiderable length of time mustelapse before the seal acquires any strength.

3,407,989 Patented Oct. 29, 1968 The time required to cool the fusedthick mass of material to a point where the heat seal will becomeselfsupporting has proven to be of such long duration that it has notbeen considered economically practical to seal bags in the manner.

In my patent, US. 3,111,794, I have proposed a method and device forproducing an improved bag closure. By this method a metal clip iscrimped around a twisted or gathered end of a bag and then a hot knifesevers the end of the bag at a short distance from the clip. The side ofthe hot knife is then pressed against the severed end of the bag so asto fuse the exposed end. In my copending application, S.N. 312,696, nowPatent No. 3,187,481, a device is disclosed whereby a length of masktapeor the like is used in lieu of the metal clip. Although both of thesetechniques produce generally satisfactory closures, there is somedifiiculty in obtaining an air-tight seal. Since the end portion of thebag extending beyond the clip or tape tends to flare outwardly when thehot knife surface is pressed against the exposed film, it is difiicultto completely fuse the end portion. This leaves tiny capillaries throughthe gathered end and thus permitting a gradual loss of vacuum in the bagover prolonged periods of time.

It is an object of the present invention to provide a method forobtaining an air tight seal on thermoplastic bags of any size, whichseal Will be relatively small and conform to the product; It is afurther object to provide a sealed thermoplastic bag having an air tightseal.

Other objects and advantages of the present invention will becomeapparent from the following detailed description of the invention takenin conjunction with the accompanying drawings wherein:

FIGURE 1 is a perspective view of the apparatus of this invention.

FIGURE 2 is a front elevational view of the apparatus of FIGURE 1.

FIGURE 3 is a top plan view of the apparatus.

FIGURE 4 is a section taken on about line 44 of FIG. 3, certain elementsbeing broken away for better clarity.

FIGURE 5 is a perspective view schematically illustrating certain stepsin the operation of the apparatus, and

FIGURE 6 is a perspective view of the final seal.

It has now been found that by employing a tape and by severing thegathered end of the bag and the tape imultaneously that a clean, smoothend is presented to the hot knife surface which will not flareoutwardly. This results in complete fusion of the severed end of the bagthus eliminating leakers.

Any suitable apparatus may be employed for gathering (or twisting) theend of the bag, severing the tape and gathered end and fusing thesevered end. A particularly suitable device is shown in my copendingapplication, Ser. No. 312,696, now US. Patent No. 3,187,481.

This device comprises, in general, a product support unit 10, a tapedispensing and clamping unit 11, a bag cut-off and sealing unit 12, anevacuating unit 13 and a tape cut-off unit 16. All units are placed upona work surface 14, e.g., a platform or floor.

The product support unit 10 is illustrated as a stationary table 15. Ifdesired the support unit could comprise a conveyor which delivers thebag product (e.g. whole ham 17 in thermoplastic bag 18) from a productbagging station (not shown).

The tape dispensing clamping unit and the bag cut-off and sealing unitare both mounted on a common carriage 19. This carriage rides on thework surface 14 and is reciprocally movable thereon. In the illustratedapparatus the carriage 19 is mounted on a plurality of wheels 20 and ismoved to and fro by a carriage mover comprising an air operated cylinder21, the piston rod 22 of which is secured to the back plate 23 of thecarriage.

The tape dispensing and clamping unit 11 is fixedly secured on the topof movable carriage 19 adjacent the side closest to the productsupporttable. The detailed construction of the tape dispenser is bestseen in FIG- URES 1 and 4, wherein it is seen that the unit cornprises asupply roll 24 of pressure sensitive adhesive tape mounted in aconventional dispenser housing (not shown). The tape 26 is drawn fromthe supply roll with the adhesive side exposed. The tape is fed underthe guide rolls 27, 28 mounted on'elongated arm 29 which extends beyondthe front side 30 of carriage 19. The face 31 of the extended end of arm29 is grooved to form a saddle 32. therein.

The clamping device 50 in the illustrated apparatus is mounted on theforward face of carriage 19 directly below extended arm 29 of the tapedispenser. A U-shaped yoke 51 which is bolted or otherwise secured tothe carriage face 30 supports the clamp. A pinion gear.52 is heldbetween the legs of the yoke 51 by a shaft 53, the respective ends ofwhich extend through the legs of the yoke a short distance. Clamp arms54 and 55 are secured to the ends of the shaft 53. The gear and clamparms are fixedly secured to the shaft so that rotation of the gearrotates the shaft, which in turn will move the clamp arms. The clamparms are shaped in a suitable manner so that the outer free ends thereofwill generally mate with the saddle 32 when the clamp is moved tooperative position. Freely rotatable rollers 57 and 58 are mountedbetween the free ends of the clamp arms in suitable manner.

The clamp is moved into operative position by means of a driven rack 60which co-operates with the pinion gear 52. The rack is moved to and froby an air cylinder 62, the piston of which is fixed to or integral withthe rack 60.

The cut-off and fuse sealing unit 12 is mounted slightly behind the tapedispensing unit. In addition to moving to and fro together with the tapedispensing unit, the cutoff unit is mounted for movement toward and awayfrom and in a direction generally perpendicular to the elongated arm 29of the tape dispenser. In the illustrated embodiment this isaccomplished by mounting the cut-off unit 12 on a second movablecarriage 33 which is independently reciprocable on top of movablecarriage 19. Carriage 33 is made movable by mounting it on a pluralityof wheels 34. Reciprocal movement is obtained from a carriage movercomprising air cylinder 35 and piston rod 36 secured to the rear side ofcarriage 33.

Near the forward top edge of the carriage 33 there are two knife guiderods 63. Knife bar 64 is bored out and mounted to ride up and down onthe guide rods. A knife air cylinder 65 is mounted on support plate 66between the rods. The plate 66 is fixedly secured to the top of carriage33- and is maintained in generally fixed vertical position by struts 70.The piston 67 of the cylinder is secured to the top of knife bar 64. Theknife bar extends towards the forward side of the apparatus. The knifeblade, per se, is secured to the extended end of the bar so that it isgenerally in the same vertical plane as the saddle groove 32 in the tapedispensing unit. The knife is designated 67 in the drawings.

The blade is heated in known manner by inserting cartridge heaters (notshown) therein. The heaters are connected to a suitable electric powersource (not shown) via flexible electric power line 68 (shown in FIGUREThe knife blade is maintained hot at all times during operation of themachine. Suitable temperatures are from about 450 to 600 Fahrenheit,depending primarily upon the particular thermoplastic from which the bag18 is made.

The evacuating unit 13 is constructed in known manner. It comprises, ingeneral, a vacuum nozzle 37 fixedly mounted on the end of rotatableconduit 38 which in turn communicates with vacuum chamber 39.Sub-atmosperic pressure is created in the chamber 39 via flexible hose40 connected to a suitable evacuation device such as a vacuum pump (notshown). Conduit 38 (and thus nozzle 37) are rotated by connection to themotor 41 via a gear reducer 42 and clutch assembly 43.

The tape cut-off unit includes knife which is secured to the'end ofpiston 81 of air cylinder 75. Ordinarily this knife is in retractedposition and is enclosed in a shield housing (not shown) for safetyreasons. The air cylinder 75 which drives the knife is mounted oncarriage 19 by a suitable support bracket 77. This bracket positions thetape cut-off knife several inches in front of the saddle grove 32 and inline with the extended arm 29 of the tape dispenser. The cutting edge 84of the knife 80 is serrated to aid in making the transverse cut in thetape 26.

The actuation of the evaporating unit 13, the carriage 19, the cut-offunit 12, the carriage 33, and the tape cut-off knife 80 is performed ina timed sequence via conventional timing circuits and switches. Thetiming mechanisms and their operation are so well known in the art thatdetailed description thereof is not deemed necessary for purposes ofunderstanding the present invention.

In operation, product (such as whole ham 17, or a turkey, chicken,primal meat cut, etc.) in a bag 18 of thermoplastic film (such as saran,polyethylene, polypropylene, etc.) is brought to a rest position onsupport unit 10. The open neck of the bag is drawn over the vacuumnozzle 37 and held around the conduit 38. The vacuum pump (not shown) isturned on and operates until the bag is substantially evacuated.

The timing device is then activated. Its first operation is activationof the drive motor '41 to Wist the nozzle 37 and make a twisted rope ofthe extended bag neck. Next the timer actuates air cylinder 21, movingcarriage 19 forward until the twisted bag neck rests in saddle 32 in thearm of the tape dispenser. Prior to this, tape is drawn from the supplyroll for a distance sufi'lcient to leave at least a short length drapedover the end of arm 29 and thus hanging in front of the saddle.

The movement of the twisted bag neck into the saddle pushes the end ofthe tape into the saddle. The clamp unit 50 is simultaneously actuatedand pushes the bag neck and tape firmly into the saddle.

At this point the timer again actuates the motor 41 so that the bag neckis further twisted. During this second twist the pressure exerted byclamp 50 is suflicient to make the tape adhere to the bag neck.Continued twisting causes further tape to be drawn from the supply rolland drawn tightly about the neck (to form an encircling sleeve 45).

Twisting of the end of the neck on the vacuum nozzle causes a shorteningof the neck which draws the bag toward the fixed end of the bag. Sincethe tape is being continuously dispensed, a portion of the tape sleeveextends beyond the edges of the clamp 50 so as to be directly under theknife 67.

The motor 41 is deactivated and air cylinder 65 is activated, drivingthe heated cut-off knife 67 down and through the tape encircling the bagneck and the twisted bag. As soon as the cut is complete, the timeractuates air cylinder 35, so that the carriage 33 moves toward the tapedispenser. The tape and bag neck are cut so as to leave no exposed edgeportions of film.

Movement of the carriage 33 axially compresses the end of the bagbetween the hot knife 67 and the tape sleeve 45 (see FIGURE 5). In avery short time (e.g. 3 to 4 seconds for saran films) the taped neck isfused into solid mass. The clamp 50 holds the tape-encircled neckportion in place so that the end of the neck cannot-move away from thehot knife. As shown in FIGURE 6 this produces a smooth fused closure.

The carriage 33 is then withdrawn and the cut-off knife is retracted. Atthe same time carriage 19 is withdrawn to its rest position, and theclamp 50 is returned to its normal position i.e., open. When carriage 19reaches its rearward rest position air cylinder 75 is actuated, drivingtape cut-oft knife 80 downward to sever the tape an inch or so in frontof the face 31 of the arm 29'. The severed tape drapes over the face 31in front of saddle groove 32 in readiness for the next cycle.

The invention has been described with emphasis on the employment ofparticular apparatus. The invention is not so limited. Any suitableapparatus may be used which gathers or twists the end of a bagcontaining product. encircling a portion of the gathered or twisted endwith a tape so as to restrain the end positions, cutting through thetape and bag and fusing the severed bag end. A-ny severing means may beemployed including a knife, hot wire, radiant heating or the like. Anysuitable fusing means may be employed including a hot flat surface,radiant heating means or the like. The term tape as employed hereinincludes any flexible self adhearing strip or band of material which maybe readily cut. A presently preferred material is masking tape.

What is claimed is:

1. A package comprising:

(a) a thermoplastic bag,

(1)) an object within said thermoplastic bag,

(c) a tightly gathered neck portion on said thermoplastic bag,

(d) a tape sleeve encircling the outer extremity of said neck portion,the outer edge of said tape sleeve and the outer edge of saidthermoplastic bag being substantially flush one to the other, and

(e) the outer edge of said thermoplastic bag that is substantially flushwith the outer edge of said tape being fused.

2. The package of claim 1 wherein said neck is twisted.

3. The package of claim 1 wherein said tape comprises a pressuresensitive adhesive tape.

References Cited UNITED STATES PATENTS 2,088,232 7/ 1937 Cumming 229-623,113,408 12/ 1963 Kirkpatrick.

3,322,325 5/ 1967 Bush 229-62 3,011,690 12/1961 Gabuzda 22962 DAVID M.BOCKENEK, Primary Examiner.

